Small ruminant reproductive loss investigation: a retrospective analysis and recommendations for optimizing diagnostic outcomes.

Abstract

OBJECTIVE: We present a retrospective evaluation of small ruminant reproductive loss investigations performed at the Iowa State University Veterinary Diagnostic Laboratory (ISUVDL) with comprehensive characterization of submission components, etiologies of reproductive losses, and assessment of factors contributing to diagnostic success. METHODS: Data from 354 small ruminant abortion submissions received at ISUVDL between January 1, 2019, and December 31, 2023, were evaluated for history completeness, sample inventory, gross and histologic lesions, culture yield, and molecular testing results. Univariate logistic regression models were employed to assess associations between achieving a definitive diagnosis and specific submission variables. RESULTS: A definitive etiology for pregnancy wastage was achieved in 50.3% of caprine and 64.6% of ovine submissions. Bacterial abortions represented the largest etiologic category, with Campylobacter jejuni accounting for the greatest share of bacterial infections (36.2% of bacterial abortions and 10.7% of all cases). Toxoplasma gondii was the single most frequently diagnosed abortifacient agent (15%), while fungal and viral abortions were rare (< 2%). Sampling and diagnostic completeness, with the inclusion of both fetus and placenta (OR, 2.61), and performance of histopathology, culture, and molecular screening in tandem (OR, 2.03) were found to have the greatest positive impact on diagnostic outcomes. CONCLUSIONS: Diagnostic outcomes are optimized by complete sampling and testing, with priority placed on comprehensive molecular screening for pathogens that are highly significant for herd health. CLINICAL RELEVANCE: This retrospective provides an in-depth summary of small ruminant abortion case data from submissions received at ISUVDL and makes recommendations for improving diagnostic outcomes in reproductive loss investigations.